Infrared inspections have seen widespread use as a maintenance tool in many environments. The cost, speed and accuracy of these inspections are constant concerns. Infrared (IR) images sometimes look quite different than the visible light view of the same scene, resulting in camera operator challenges in targeting the intended points of interest within a scene. Often a scene of interest during an infrared inspection will have a regular pattern of electromechanical devices. Examples might include rows of circuit breakers, a whole wall of electrical panels, or even multiple lines of regularly laid out machinery. Within the pattern of devices, visible light images in a limited field of view may look quite regular, but in the infrared domain these images may be radically different depending on the loads applied to each device in the scene or even due to some fault in the equipment. Proper and rapid identification of the equipment in thermal contrast is an essential ingredient to the infrared inspection. Hence a reliable method to quickly and accurately identify a point in the visible light domain and relate it to a point in the IR domain is essential.
Camera operators benefit from target location aids, such as lasers to point to a target in view, and/or related views of visible light and IR light images displayed in a coordinated fashion.
Inspections also can be slowed by a need to record other pertinent data, such as the size of the object being viewed, or even the distance to the target and these parameters can be determined from some of the same solutions to the target location challenges noted above. For example, in energy efficiency investigations, an operator can use an infrared camera equipped with a mapping of pixel size to viewed area and typical thermal analysis tools to determine heat loss and compute the radiant energy from a target object and even calculate the cost of the heat loss.
Additionally, based upon the type of analysis that the infrared camera is designed to accomplish, it would be beneficial if a display was provided to the operator in which either a visible image is fused onto the infrared image in a single display or the infrared image and the visible image would be provided side by side on the display.
U.S. Patent Application Publication Nos. 2006/0249679 and 2006/0289772, both to Johnson et al describe an infrared camera or sensor combined with a visible image. U.S. Patent Application Publication No. 2006/0289772 produces a field of view displayed in various display modes including providing a full screen visible image, a full screen infrared image or a blended combination of the visible and infrared images. As can be appreciated, the optics which are utilized to produce both the visible and infrared images are offset from one another. Consequently, when the images are blended, a parallax problem is created. As described in paragraph [0012], the parallax problem is dealt with by registering the images from the visible camera with the images from the infrared camera module on a single display and displacing the images relative to each other until they are registered utilizing a manual adjustment mechanism. Additionally, it is noted that a laser pointer may be employed in both of the Johnson et al applications.
U.S. Pat. No. 7,034,300, issued to Hamrelius et al describes an infrared camera provided with optics for focusing the camera onto an object to be recorded on a display. A narrow light source is provided offset from the display, a distance meter and the optics. A processor is provided for controlling the operation of the camera as well as controlling a parallax compensation device. An example of this parallax compensation device would be a motor which would mechanically change the angle of the laser source.
However, neither of the Johnson et al patent application publications as well as the Hamrelius et al patent describe a system provided with a display onto which both a visible and infrared image is projected as well as provided with one or two shaped beam light sources for targeting the object to be projected onto the display. Additionally, the prior art requires the target distance be known in order to correct for the parallax error created by the separation of the targeting aid and the infrared camera.
Additionally, since the Hamrelius patent describes a camera using a narrow light source to identify a target point, computation is needed to compensate for parallax. The use of a shaped beam with an axis, i.e. a relatively wide beam, does not require a computation to correct for parallax.
Also, the prior art specifies the use strictly visible light sources; this invention can provide parallax correction, distance calculation, area calculation and align a visible light image while using any light energy to which the targeting aid imager is sensitive; this is a useful point given that common “visible light” cameras are sensitive to near infrared energy outside the visible light spectrum.